An eco-friendly wood sponge-based multifunctional pressure and temperature sensor for electronic skin

Electronic skin (e-skin) aims to mimic human skin functions, which could profoundly affect medical care and robots. However, it still faces challenges in simultaneously detecting and distinguishing pressure and temperature signals in real-time. Herein, a simple and sustainable strategy is proposed to fabricate a reduced graphene oxide (rGO)-coated wood sponge (rGO@WS) for a multifunctional sensor with high pressure and temperature properties. The prepared porous wood sponge presents high elasticity and superior durability. The added rGO endows the sponge with high conductivity and excellent fatigue resistance. The proposed sensor can realize high sensitivity (1.18 kPa−1), a large pressure range (0.2–100 kPa), a low detection limit and can also detect the temperature with a minimal detection limit of 0.6 K and a response time of 0.8 s. Due to the different response principles of piezoresistive and thermoelectric effects, pressure sensing performance and temperature sensing performance are independent. Meanwhile, a 4 × 4 pixel sensing array based on the rGO@WS sensor is fabricated to serve as e-skin to detect and distinguish pressure and temperature signals. This work sheds new light on the development of wearable devices and e-skin for health care.